/*
 * Copyright (c) 1997, 2003, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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 */

package java.rmi.activation;

/**
 * General exception used by the activation interfaces.
 *
 * <p>As of release 1.4, this exception has been retrofitted to conform to
 * the general purpose exception-chaining mechanism.  The "detail exception"
 * that may be provided at construction time and accessed via the public
 * {@link #detail} field is now known as the <i>cause</i>, and may be
 * accessed via the {@link Throwable#getCause()} method, as well as
 * the aforementioned "legacy field."
 *
 * <p>Invoking the method {@link Throwable#initCause(Throwable)} on an
 * instance of <code>ActivationException</code> always throws {@link
 * IllegalStateException}.
 *
 * @author Ann Wollrath
 * @since 1.2
 */
public class ActivationException extends Exception {

  /**
   * The cause of the activation exception.
   *
   * <p>This field predates the general-purpose exception chaining facility.
   * The {@link Throwable#getCause()} method is now the preferred means of
   * obtaining this information.
   *
   * @serial
   */
  public Throwable detail;

  /**
   * indicate compatibility with the Java 2 SDK v1.2 version of class
   */
  private static final long serialVersionUID = -4320118837291406071L;

  /**
   * Constructs an <code>ActivationException</code>.
   */
  public ActivationException() {
    initCause(null);  // Disallow subsequent initCause
  }

  /**
   * Constructs an <code>ActivationException</code> with the specified
   * detail message.
   *
   * @param s the detail message
   */
  public ActivationException(String s) {
    super(s);
    initCause(null);  // Disallow subsequent initCause
  }

  /**
   * Constructs an <code>ActivationException</code> with the specified
   * detail message and cause.  This constructor sets the {@link #detail}
   * field to the specified <code>Throwable</code>.
   *
   * @param s the detail message
   * @param cause the cause
   */
  public ActivationException(String s, Throwable cause) {
    super(s);
    initCause(null);  // Disallow subsequent initCause
    detail = cause;
  }

  /**
   * Returns the detail message, including the message from the cause, if
   * any, of this exception.
   *
   * @return the detail message
   */
  public String getMessage() {
    if (detail == null) {
      return super.getMessage();
    } else {
      return super.getMessage() +
          "; nested exception is: \n\t" +
          detail.toString();
    }
  }

  /**
   * Returns the cause of this exception.  This method returns the value
   * of the {@link #detail} field.
   *
   * @return the cause, which may be <tt>null</tt>.
   * @since 1.4
   */
  public Throwable getCause() {
    return detail;
  }
}
